GitHub user zsxwing opened a pull request:
https://github.com/apache/spark/pull/18177
[SPARK-20955][Core]Intern "executorId" to reduce the memory usage
## What changes were proposed in this pull request?
In [this
line](https://github.com/apache/spark/blob/f7cf2096fdecb8edab61c8973c07c6fc877ee32d/core/src/main/scala/org/apache/spark/scheduler/cluster/CoarseGrainedSchedulerBackend.scala#L128),
it uses the `executorId` string received from executors and finally it will go
into `TaskUIData`. As deserializing the `executorId` string will always create
a new instance, we have a lot of duplicated string instances.
This PR does a String interning for TaskUIData to reduce the memory usage.
## How was this patch tested?
Manually test. Test codes:
```
for (_ <- 1 to 10) { sc.makeRDD(1 to 1000, 1000).count() }
Thread.sleep(2000)
val l =
sc.getClass.getMethod("jobProgressListener").invoke(sc).asInstanceOf[org.apache.spark.ui.jobs.JobProgressListener]
org.apache.spark.util.SizeEstimator.estimate(l.stageIdToData)
```
This PR reduces the size of `stageIdToData` from 3487280 to 3009744 (86.3%)
in the above case.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/zsxwing/spark SPARK-20955
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/18177.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #18177
----
commit 38a4e31d6c9ed3d2b459737553144f0fae5b0934
Author: Shixiong Zhu <shixi...@databricks.com>
Date: 2017-06-01T19:33:58Z
Intern "executorId" to reduce the memory usage
----
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